Technical Field
The present invention relates to a closed-loop anti-shake structure, and more particularly, to a closed-loop anti-shake structure applicable to lens driving apparatuses.
Description of Related Art
With the advancement in technology, camera devices are more and more popular. However, as the camera device is often operated without being secured with a tripod, the shutter speed may be below a safe level under insufficient lighting, thus when the shutter is pressed, blurry images may be produced easily due to various kinds of shakes.
Electronic and optical compensation methods are two main anti-shake methods used in the existing camera devices. The electronic compensation method utilizes an electronic system of a camera device to control the capturing of images, employs an algorithm to restore images, or involves selection of the clearest image among several continuously shot images. The optical compensation method involves moving an optical lens module or a light sensing module to perform the compensation operation so as to offset the shake of the camera and thereby to maintain the stability of the camera's optical system.
With an increasing demand for good image quality and functionality, a camera device's anti-shake system can be influenced by an ambient magnetic field easily when a Hall sensor is adopted to perform the image compensation operation. Moreover, the conduction of the electric circuit is required when the Hall sensor is used for anti-shake control in the direction of the ray axis, resulting in increased manufacturing and development costs. All manufacturers have a common objective of developing a lens driving apparatus with a closed-loop anti-shake structure that is capable of reducing magnetic field interference and costs.